@book { VonderLeonorezumFidelio,
    title = "Von der «Leonore» zum «Fidelio»",
    subtitle = "Vorträge und Referate des Bonner Symposions 1997",
    author = "Helga {Lühning} and Wolfram {Steinbeck}",
    year = "2000",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1089414"
}